A wireless communication system has been developed to offer a voice service and a data service while keeping user's mobility. A wireless communication system may be formed of a radio access network, a core network, and the other elements. User equipment (UE) is wirelessly connected with a certain element, i.e., an eNB, of the radio access network, whereas the radio access network, the core network, and nodes of the core network are mainly wire-connected with each other.
Since wireless resources are generally limited in comparison with wired resources, there is a strong possibility that the lack of wireless resources will be caused between the UE and the radio access network. This situation of facing with the lack of wireless resources between the UE and the radio access network is referred to as congestion of the radio access network.
In 3GPP (3rd Generation Partnership Project), the eNB is forced to obviate the congestion of the radio access network. Specifically, if any congestion occurs in the radio access network, this congestion is obviated in a way of abandoning data transmission rather than reducing a communication speed when it is not possible any more to guarantee a required communication speed with regard to GBR (Guaranteed Bit Rate) data that require a guarantee of a communication speed on a certain level, and in a way of reducing a communication speed with regard to non-GBR data that require no guarantee of a communication speed on a certain level. In case of non-GBR data, downlink data are transmitted to the radio access network through the packet data network (PDN) and the core network at the same communication speed as in any non-congestion situation. However, since the radio access network fails to deliver such data to the UE at the same communication speed as in any non-congestion situation, such data are accumulated in a buffer of the eNB or selectively abandoned by the eNB. Meanwhile, uplink non-GBR data to be delivered from the UE to the radio access are accumulated in a buffer of the UE or selectively abandoned by the UE due to an insufficient allocation of resources from the radio access network.
Current technique to obviate congestion of downlink and uplink data has some drawbacks that data are uniformly treated without any consideration for data characteristics such as a user of data, a channel of data transmission, or a type of data, and that downlink data are delivered to the radio access network through the core network without distinction of congestion or non-congestion situation and thereby much data, which are incapable of being properly transmitted to the UE by the eNB in a congestion situation, are unnecessarily delivered to the radio access network.
Accordingly, required is new technique to obviate congestion by considering data characteristics and involving the core network and the UE therein.